I got aroused by the sight of my wife's sisters, who were living with us, exposing their panties and naked in the bathroom. When they noticed, they stared at my dick with passionate eyes. When I rubbed my dick against my sister's plump ass while my wife wasn't looking, she didn't refuse and instead let me fuck her secretly, hiding from the rest of the family. It's a dangerous relationship, so I get so excited that I wet myself.